We stayed in Dieppe a year or two back.
I'm only posting to save you making the same mistake.

Wasn't that bad, but if you want a more French part of coastal northern France it was ok nice.
I'll try & find the name of the site we happened upon. Wasn't the one we stayed on, hell no, that was a shit hole, but this place was idyllic. Had a pool etc, & a little river trickling through. I'd got it in mind if we are over that way again. I'll have a look for you...

We made the mistake of staying at Camping Vitamin.
Ghastly was an understatement.

La Source was a km or two out of Dieppe. As a town, Dieppe was ok. Beach, really good outdoor Lido thing. We spent a day following little lanes down the coast. Some nice little spots. But it's not a very touristy part of France, & we liked it. It was about 2hrs to Calais, & that was towing a Chavavan.
La Source was nice though. We discovered it on such a foray around the local villages etc. After Vitamin it was very nice. Little pool, small bar etc.

We are off again in a week or so, but to DisneyIand Paris after happening on a much cheaper way of doing it, than buying multiple days.